1. Field of the Invention
The present invention relates to a skin or hair washing composition, such as hair shampoo or body shampoo, containing an adduct of an alkylene oxide having 2 to 4 carbon atoms linked to an alcohol having 8 to 10 carbon atoms (alkylene glycol ether), a surfactant and a specific cationic polymer.
2. Background of the Invention
Washing compositions are required to have various functions such as emulsifying power, solubilizing power or washing power against dirt components such as oil. Among them, a washing composition for the skin or the hair, as contrasted with any detergent composition for industrial use, is required to have good foaming properties and improved feeling upon use, such as good foamability and comfortable foam sensation during washing, and nice touch during rinsing or after drying (in the case of hair, finger-combability or softness of the hair, and in the case of the skin, ease of rinsing or the moist feeling after drying).
With the aim of improving the foaming properties or of adjusting the viscosity of washing compositions, a variety of foam enhancers and thickening agents have been developed so far, and fatty acid alkanolamides, fatty acid amidopropyl betaines or the like is typically used as a foam enhancer or thickening agent. However, these nitrogen-containing compounds tend to undergo color changes over time, depending on the mixing conditions thereof. Furthermore, fatty acid diethanolamide is suspected of causing carcinoma, when becoming a nitroso compound (i.e., one of the impurities thereof). For these reasons, there is an urgent need for developing a thickening/foam-enhancing agent containing no nitrogen.
Patent Document 1 describes a washing composition excellent in foamability as a thickening/foam-enhancing agent containing no nitrogen, obtained by employing an alcohol having 8 to 12 carbon atoms as a starting material, and comprising a combination of a (poly)ethylene glycol alkyl ether added with 1 to 3 moles of ethylene oxide, an anionic surfactant and/or a ampholytic surfactant.
Patent Documents 2 and 3 also disclose alkylene oxide adducts of higher aliphatic alcohols with short-chained ethylene oxide or propylene oxide introduced thereto, and these products are described to have improved foamability and improved low temperature stability. However, none of these documents make mention of the improvement of feeling upon use, and there is no mention about use of cationic polymers, either. These methods are also far from satisfactory in feeling upon use, especially in a feeling upon use required for a skin or hair washing composition.
Washing compositions for the skin or the hair are known to make use of cationic polymers, in order for the feeling of touch to be improved. Patent Document 4 is reported to have conducted a research about the improvement of a feeling upon use by combining a cationic polymer with a combination of dialkylene glycol which is an alkylene glycol ether of a short-chained alcohol, and an anionic surfactant. Yet this method is not enough to obtain sufficient foamability.
Any of the foregoing documents has yet to satisfy excellent foamability and excellent feeling upon use in parallel. Under such a circumstance, there has been a strong demand for the development of a skin or hair composition which is not only excellent in foamability, but also can enjoy a good feeling upon use in the process from washing to after drying.    [Patent Document 1] JP-A No. 2004-277685    [Patent Document 2] JP-A No. 11-12594    [Patent Document 3] JP-A No. 7-53991    [Patent Document 4] JP-A No. 4-108723